The final audit of the 2020 Census Post-Enumeration Survey (PES) results related to overcounts and undercounts was released by the Commerce Department Inspector General (IG), questioning their validity and recommending improvements for 2030.
While deeming the methodologies used to be “consistent with federal and bureau statistical standards,” the IG “identified areas of concern that had an impact on the survey results, bringing into question the validity of the 2020 PES. Specifically, we found the following: I. Operational disruptions and mitigations in response to missing data increased uncertainty in PES estimates. A. The 2020 PES experienced increased levels of missing data. B. The bureau did not always quantify sources of non-sampling error. II. A smaller-than-anticipated sample size contributed to increased uncertainty in PES estimates. III. The bureau did not carry out quality control (QC) processes for PES operations as planned. A. QC listers did not complete Independent Listing QC checks and rectification within the prescribed timelines. B. The bureau did not conduct Person Interview Reinterview within recommended completion time frames. C. The bureau reviewed fewer Basic Collection Units than planned during clerical matching and did not always review flagged cases.”
The IG concluded that the Census Bureau “should execute timely” quality control “processes as designed to ensure that the results of PES operations are accurate, consistent, and reliable.”
Among the IG’s recommendations for improvement “when implementing changes to the 2030 PES redesign” were:
- “Advancing approaches to mitigate missing data and conducting research to better understand groups most likely to be impacted by missing data.”
- “Analyzing and quantifying major sources of non-sampling error, to include the cumulative effect of multiple sources of error, and ensuring the results are communicated to the public.”
- “Ensuring that sampling designs undergo appropriate analysis prior to production and are designed to support their intended uses.”
- “Establishing a detailed and effective strategy to ensure computer system relocations are completed on schedule to minimize operational disruptions.”
- “Ensuring changes to quality assurance processes are documented, approved, and widely communicated across all affected divisions and their operational components.”
- “Strengthening the bureau’s quality assurance plan to ensure reinterviewers complete cases within prescribed time frames.”
- “Strengthening the clerical matching QC plan to adhere to applicable QC review thresholds.”
- “Establishing procedures to ensure analysts review flagged clerical matching cases and documentation of analyst reviews is maintained.”
- “Ensuring that the bureau’s records retention schedule for 2030 Census records prescribes only fixed retention periods that also allow records to be available for a sufficient period following the end of operations for internal and external oversight activities.”
The Census Bureau disputed the IG’s conclusions but “acknowledged that there are opportunities to strengthen future surveys.”
– The Census Bureau Should Address Challenges from the 2020 Post-Enumeration Survey Ahead of the 2030 Census. FINAL REPORT NO. OIG-25-015-A. MARCH 25, 2025
Inspector General Questions Validity of 2020 Census Post-Enumeration Survey
The final audit of the 2020 Census Post-Enumeration Survey (PES) results related to overcounts and undercounts was released by the Commerce Department Inspector General (IG), questioning their validity and recommending improvements for 2030.
While deeming the methodologies used to be “consistent with federal and bureau statistical standards,” the IG “identified areas of concern that had an impact on the survey results, bringing into question the validity of the 2020 PES. Specifically, we found the following: I. Operational disruptions and mitigations in response to missing data increased uncertainty in PES estimates. A. The 2020 PES experienced increased levels of missing data. B. The bureau did not always quantify sources of non-sampling error. II. A smaller-than-anticipated sample size contributed to increased uncertainty in PES estimates. III. The bureau did not carry out quality control (QC) processes for PES operations as planned. A. QC listers did not complete Independent Listing QC checks and rectification within the prescribed timelines. B. The bureau did not conduct Person Interview Reinterview within recommended completion time frames. C. The bureau reviewed fewer Basic Collection Units than planned during clerical matching and did not always review flagged cases.”
The IG concluded that the Census Bureau “should execute timely” quality control “processes as designed to ensure that the results of PES operations are accurate, consistent, and reliable.”
Among the IG’s recommendations for improvement “when implementing changes to the 2030 PES redesign” were:
- “Advancing approaches to mitigate missing data and conducting research to better understand groups most likely to be impacted by missing data.”
- “Analyzing and quantifying major sources of non-sampling error, to include the cumulative effect of multiple sources of error, and ensuring the results are communicated to the public.”
- “Ensuring that sampling designs undergo appropriate analysis prior to production and are designed to support their intended uses.”
- “Establishing a detailed and effective strategy to ensure computer system relocations are completed on schedule to minimize operational disruptions.”
- “Ensuring changes to quality assurance processes are documented, approved, and widely communicated across all affected divisions and their operational components.”
- “Strengthening the bureau’s quality assurance plan to ensure reinterviewers complete cases within prescribed time frames.”
- “Strengthening the clerical matching QC plan to adhere to applicable QC review thresholds.”
- “Establishing procedures to ensure analysts review flagged clerical matching cases and documentation of analyst reviews is maintained.”
- “Ensuring that the bureau’s records retention schedule for 2030 Census records prescribes only fixed retention periods that also allow records to be available for a sufficient period following the end of operations for internal and external oversight activities.”
The Census Bureau disputed the IG’s conclusions but “acknowledged that there are opportunities to strengthen future surveys.”
– The Census Bureau Should Address Challenges from the 2020 Post-Enumeration Survey Ahead of the 2030 Census. FINAL REPORT NO. OIG-25-015-A. MARCH 25, 2025
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